Question

Harry is trying to solve the equation y = 2x2 − x − 6 using the quadratic formula. He has made an error in one of the steps below. Find the step where Harry went wrong. Step 1: x equals the negative of negative 1 plus or minus the square root of the quantity negative one squared minus 4 times 2 times negative six, end quantity, all over 2 times 2. Step 2: x equals the negative of negative 1 plus or minus the square root of negative one plus forty-eight all over two times 2. Step 3: x equals the negative of negative 1 plus or minus the square root of forty-seven all over two times 2. Step 4: x equals 1 plus or minus the square root of forty-seven all over 4.

Answer 1

I believe it would be step number 2... I am not very sure...

Answer 2

Answer:

Error is in step 2

Step-by-step explanation:

Harry is trying to solve the equation y = 2x^2 − x − 6 using the quadratic formula. He has made an error in one of the steps below.

Step 1: $x= \frac{-(-1)+-\sqrt{(-1)^2-4(2)(-6)} }{2(2)}$

Step 2: $x= \frac{-(-1)+-\sqrt{-1+48}}{2(2)}$

Step 3:  $x= \frac{-(-1)+-\sqrt{47}}{2(2)}$

Step 4:   $x= \frac{1+-\sqrt{47}}{4}$

Quadratic formula is

 $x= \frac{-(b)+-\sqrt{(b)^2-4(a)(c)} }{2(a)}$

From the given equation a= 2, b= -1  and c= -6

plug in all the values in the formula

Step 1: $x= \frac{-(-1)+-\sqrt{(-1)^2-4(2)(-6)} }{2(2)}$

Step 1 is correct

(-1)^2 = -1  times -1 = +1 (negative times negative is positive)

Instead of +1 , Harry used -1 inside the square root

So the error is in step 2

Step 2: $x= \frac{-(-1)+-\sqrt{1+48}}{2(2)}$